<html>
    <head>
        <script src="https://cdn.jsdelivr.net/npm/vue@2.6.12"></script>
    </head>
    <body>
        <div id="app">
           <button v-on:click="a++">a+1</button>
           <button v-on:click="b++">b+1</button>
           <p>number+a={{add1()}}</p>
           <p>number+b={{add2()}}</p>
        </div>
        <script>
            new Vue({
                el:'#app',
                data:{
                    a:0,
                    b:0,
                    number:30
                },
                methods:{
                    add1:function(){
                       console.log("number+a");
                       return this.a+this.number
                    },
                    add2:function(){
                       console.log("number+b");
                       return this.b+this.number
                    }
                }
            })
        </script>
    </body>
</html>